PTC thermistors as heating elements
Rectangular, 400 V
Series/Type:
Date:
B59249R*
January 2016
© EPCOS AG 2016. Reproduction, publication and dissemination of this publication, enclosures hereto and the
information contained therein without EPCOS' prior express consent is prohibited.
EPCOS AG is a TDK Group Company.
Heating elements
Rectangular, 400 V
R249
Applications
Automotive applications
cabin heating in electric vehicles
cabin heating in plug-in hybrid electric
vehicles
battery heating
Features
Aluminum metallization
Suitable for clamp contacting
Self-regulating
RoHS-compatible
Options
Other dimensions and ratings on request
Delivery mode
Packed in cardboard boxes
General technical data
Max. operating voltage
Rated voltage
Operating temperature range
Operating temperature range
Tolerance of R
R
Curvature
Dimensional drawing
Dimensions in mm
(V = 0)
(V = V
R
)
V
max
V
R
T
op
T
op
∆R
R
600
400
40/+200
40/+100
±35
< 0.05
V DC
V DC
°C
°C
%
mm
Electrical specification and ordering code
T
ref
V
BD
(typ.) (V
meas
≤
1.5 V)
°C
V
155
1000
R
min
(V = V
R
)
Ω
220
T
surf 1)
(V = V
R
)
°C
190
R
R
(V
meas
≤
1.5 V)
Ω
3000
Ordering code
B59249R0155B010
1) Temperature measurement is contactless. Voltage is provided by the power supply via pin contacts (diameter 2.5 mm).
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 2 of 9
Heating elements
Rectangular, 400 V
R249
Reliability data
Test
Electrical endurance,
cycling
Electrical endurance,
constant
Damp heat
Standard
IEC 60738-1
IEC 60738-1
IEC 60738-1
Test conditions
Room temperature, V
max
Number of cycles: 10 000
Storage at V
max
and T
op,max
(@ V
R
)
Test duration: 1000 h
Temperature of air: 40
°C
Relative humidity of air: 93%
Duration: 56 days
Test according to IEC 60068-2-78
∆R
25
/R
25
< 25%
< 25%
< 25%
Characteristics (typical)
PTC resistance R
PTC
versus PTC temperature T
PTC
measured by applying short voltage pulses at
two different voltage levels V
pulse
.
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 3 of 9
Heating elements
Rectangular, 400 V
R249
Cautions and warnings
General
EPCOS thermistors are designed for specific applications and should not be used for purposes
not identified in our specifications, application notes and data books unless otherwise agreed
with EPCOS during the design-in-phase.
Ensure suitability of thermistor through reliability testing during the design-in phase. The ther-
mistors should be evaluated taking into consideration worst-case conditions.
Storage
Store thermistors only in original packaging. Do not open the package prior to processing.
Storage conditions in original packaging: storage temperature 25
°C
... +45
°C,
relative hu-
midity
≤75%
annual mean, maximum 95%, dew precipitation is inadmissible.
Avoid contamination of thermistors surface during storage, handling and processing.
Avoid storage of thermistor in harmful environment with effect on function on long-term opera-
tion (examples given under operation precautions).
Use thermistor within the following period after delivery:
Through-hole devices (housed and leaded PTCs): 24 months
Motor protection sensors, glass-encapsulated sensors and probe assemblies: 24 months
Telecom pair and quattro protectors (TPP, TQP): 24 months
Leadless PTC thermistors for pressure contacting: 12 months
Leadless PTC thermistors for soldering: 6 months
SMDs in EIA sizes 3225 and 4032, and for PTCs with metal tags: 24 months
SMDs in EIA sizes 1210 and smaller: 12 months
Handling
PTCs must not be dropped. Chip-offs must not be caused during handling of PTCs.
The ceramic and metallization of the components must not be touched with bare hands. Gloves
are recommended.
Avoid contamination of thermistor surface during handling.
Soldering (where applicable)
Use rosin-type flux or non-activated flux.
Insufficient preheating may cause ceramic cracks.
Rapid cooling by dipping in solvent is not recommended.
Complete removal of flux is recommended.
Standard PTC heaters are not suitable for soldering.
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 4 of 9
Heating elements
Rectangular, 400 V
R249
Mounting
Electrode must not be scratched before/during/after the mounting process.
Contacts and housing used for assembly with thermistor have to be clean before mounting. Es-
pecially grease or oil must be removed.
When PTC thermistors are encapsulated with sealing material, the precautions given in chapter
"Mounting instructions", "Sealing and potting" must be observed.
When the thermistor is mounted, there must not be any foreign body between the electrode of
the thermistor and the clamping contact.
The minimum force and pressure of the clamping contacts pressing against the PTC must be
10 N and 50 kPa, respectively. In case the assembly is exposed to mechanical shock and/ or
vibration this force should be higher in order to avoid movement of the PTC during operation.
During operation, the thermistor’s surface temperature can be very high. Ensure that adjacent
components are placed at a sufficient distance from the thermistor to allow for proper cooling at
the thermistors.
Ensure that adjacent materials are designed for operation at temperatures comparable to the
surface temperature of thermistor. Be sure that surrounding parts and materials can withstand
this temperature.
Avoid contamination of thermistor surface during processing.
Operation
Use thermistors only within the specified temperature operating range.
Use thermistors only within the specified voltage and current ranges.
Environmental conditions must not harm the thermistors. Use thermistors only in normal at-
mospheric conditions. Avoid use in deoxidizing gases (chlorine gas, hydrogen sulfide gas, am-
monia gas, sulfuric acid gas etc), corrosive agents, humid or salty conditions. Contact with any
liquids and solvents should be prevented.
Be sure to provide an appropriate fail-safe function to prevent secondary product damage
caused by abnormal function (e.g. use VDR for limitation of overvoltage condition).
This listing does not claim to be complete, but merely reflects the experience of EPCOS AG.
Display of ordering codes for EPCOS products
The ordering code for one and the same EPCOS product can be represented differently in data
sheets, data books, other publications, on the EPCOS website, or in order-related documents
such as shipping notes, order confirmations and product labels.
The varying representations of
the ordering codes are due to different processes employed and do not affect the
specifications of the respective products.
Detailed information can be found on the Internet
under www.epcos.com/orderingcodes
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 5 of 9
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